well the stock block heater finaly gave out, (200K) bought a 1500 watt circulating heater, took the stock block heater out ( located in front of turbo on block) used a pipe bushing to reduce down to 3/8 pipe, hooked hose from there to heater intake, heater out went to heater hose that goes to radiator ( T into this hose ) works a lot better than stock, as soon as i start it the temp starts to move off 140 and there is allready heat at the heater vent. it was -25 F the other day and no worries.

 

just in case, does yours have a little check ball that rattles in the heater when running? if so from time to time listen for it, mine jammed and the heater overheated and ruptured